This is a competitive renewal of a training grant from the nephrology program at Washington University which has been funded for 21 years, currently at 6 post-doctoral positions per year. The program aims to train about 50% M.D. trainees and 50% Ph.D. (or M.D./Ph.D.) trainees to do basic and clinical research in areas related to kidney disease. Trainees are selected from M.D. applicants applying through the nephrology clinical fellowship program at Washington University, unsolicited outside applicants and the FASEB placement service for Ph.D. scientists. Selection is made by a selection committee including the training program director and selected faculty. Support may be offered for 1 to up to 4 years of research training. Training is conducted on a preceptor basis utilizing a group of 26 faculty derived primarily from the Nephrology Division at Washington University but including individuals in other departments and in the basic sciences. Generally, trainees appear to spend all of their research training with a single mentor. The research interests represented by the faculty include the following: basic and clinical studies of renal growth factors and kidney specific genes in normal renal physiology, renal growth and renal injury; clinical studies of growth factors in renal failure, mechanisms of renal development, mechanisms of progressive renal disease; clinical research on calcium/ phosphate/vitamin D abnormalities in renal failure, renal metabolic and biochemical adaptations to renal disease, tubular transport processes, disease mechanisms in glomerulonephritis and transplant rejection, renal response to various hormones, regulation of sodium-potassium-ATPase, mechanisms of obstructive uropathy, regulation of renal cyclooxygenase expression, and biological role of atrial natriuretic factors and studies of vascular access thrombosis. These projects are generally of long standing and well-funded. They employ a range of modern cellular and molecular technologies. Trainees are assigned individual research projects in the preceptor's laboratory with training supplemented with appropriate conferences and other meetings.